Grinding wheel advancing apparatus

ABSTRACT

The apparatus of this disclosure is for advancing the grinding wheel axially for grinding the radial surface of a workpiece. The actual advance of the wheel is caused by a piston and cylinder combination, wherein the piston is connected to the wheel mounting and the cylinder is free to move in the direction opposite to that of the piston except for a restraining force imposed by a spring. The movement of the piston is stopped by the engagement of the grinding wheel with the work with fluid under pressure causing the cylinder to move against the action of the spring. The movement of the cylinder provides a signal which cuts off the supply of fluid under pressure to the cylinder and the cylinder is locked against further movement. At the same time, the metering device is actuated which directs a predetermined volume of fluid to the cylinder. The piston advances the grinding wheel in accordance with this predetermined volume of fluid under pressure to advance the wheel against the work by a predetermined amount for a predetermined depth of cut on the workpiece.

United States Patent Price 51 Jan. 25, 1972 [54] GRINDING WHEEL ADVANCING APPARATUS Ralph E. Price, Waynesboro, Pa.

[52] U.S.Cl ..5l/165.9,5l/105 SP [51 Int. Cl ..B24b 49/08 [58] Field oiSearch ..51/l65.77, 165.8, 165.9, 165.91, 51/165.92, 105 EC; 105 SP [56] References Cited UNITED STATES PATENTS 2,101,794 12/1937 Flygare ..51/105 SP 2,961,808 11/1960 Dunigan ..51/165.92

2,984,952 5/1961 Gebel ...51/165.9

Primary Examiner Lester M. Swingle Attorney-David S. Urey 571 I ABSTRACT The apparatus of this disclosure is for advancing the grinding wheel axially for grinding the radial surface of a workpiece.

- The actual advance of the wheel is caused by a piston and cylinder combination, wherein the piston is connected to the wheel mounting and the cylinder is free to move in the direction opposite to that of the piston except for a restraining force imposed by a spring. The movement of the piston is stopped by the engagement of the grinding wheel with the work with fluid under pressure causing the cylinder to move against the action of the spring. The movement of the cylinder provides a signal which cuts off the supply of fluid under pressure to the cylinder and the cylinder is locked against further movement. At the same time, the metering device is actuated which directs a predetermined volume of fluid to the cylinder. The piston advances the grinding wheel in accordance with this predetermined volume of fluid under pressure to advance the wheel against the work by a predetermined amount for a 3,145,507 3/1964 Price BI 81 l/l SP predetermined depth of cut on the workpiece. 3,145,508 8/1964 Price ..5 H1659 X 3,473.269 10/1969 Sattler et al ..51/165.77 X 12 Clams, 7 Drawmg Figures l0 MI D 73 7| 72 7 54 ;98 56 e3; s! i 59 59 68 1 42 e9 66 e7 52 1 ka-1 hr A PATENTED M2 1972 SHEET 1 [If 6 g g I M g0 a, m 32 g E g i Y 23 33 2 8 1 Q 33 75:8

FIG.I

FIGS

i INVENTOR RALPH E. PRICE ATTORNEY PATENTEU JANZS i872 SHEET 2 OF 6 INVENTOR RALPH E. PRICE %NEY PATENTED JAN25 i972 SHEET 3 OF 6 FIG.3

MAXIMUM MOVEMENT INVENTOR RALPH E. PRICE ATTORNEY PATENTEU JAN25 m2 SHEET 1} 0F 6 av 0H 33s INVENTOR RALPH E. PRICE Ev QE PATENTEU M25197? SHEET 5 BF 6 x25. 5&3

E30 25% X w E THE 35% aw oE SE wzEzEu gym EEw aunt j mew I, E; g SE 359m 81 i; SH 338 INVENTOR RALPH E. PRICE ATTORNEY PATENTED JANZS 1972 3,636,664

SHEET 6 OF 6 48CR| 50cm k w 5% INFEED W AUTO SIDEWALL FACING OFIF OIN 42cm FEED STOP K 4% Q3 u 2 AUTOMATIC T l 65CR2 l n/ ms I5LS FEED COMPLETION SIDEWALL FEED COMPLETION FEED COMPLETION N L \L* K? 21cm 42CR2 [6L8 FEED START 47cm SIDEWALL FEED 'llrll-%l*\fi* P89 escaa 27c 2 SIDEWALL FAc|Ns ms R .l SIDEWALL FEED I 1A SIDEWALL '*-|r W APPROACH 660R! C m SIDEWALL CLAMP |f |F CR SIDEWALL FEED l START 14cm mm H M SIDEWALL FEED IF U DELAY 27cm I3SOL q GRINDING FEED IF 3mm I680L FEED STOP 4O/\/--Q 65GB! ZYSOL SIDEWALL FEED 66CR2 26SOL SIDEWALL APPROACH 15cm 3lSOL SlDEWALL FEED START 74cm 32SOL SIDEWALL CLAMP F: W

INVENTOR 5 RALPH E. PRICE ATTORNEY GRINDING WHEEL ADVANCING APPARATUS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates in general to new and useful improvements in grinding machines, and more particularly, a sidewallfacing attachment for automatically providing a controlled longitudinal feed movement for a machine, particularly for a numerically controlled grinding machine. The invention has application on cylindrical grinding machines, as well as surface grinders, and has special application when it is desirable to advance a grinding wheel a predetermined amount to provide a depth of cut sufficient to remove any runout from the annular or radial surface of a sidewall or shoulder of a cylindrical workpiece while an adjacent diameter is being ground.

2. Description of the Prior Art Prior to this invention, sidewall or shoulder-facing was obtained by a manual-lever-operated shoulder-grinding attachment which advanced the wheel spindle longitudinally against the thrust load built into the grinding wheel spindle. The transverse handwheel could also be used to advance the carriage and shoulder of the workpiece against the side of the grinding wheel. The manual device required the attention of an operator, and was subject to human error. Also, in a machine which is otherwise automatically controlled, it would be wasteful of time and money to manually control the advance of the grinding wheel.

SUMMARY OF THE INVENTION In accordance with the invention, the machine includes a grinding wheel and facilities for supporting and rotating the wheel and for supporting the workpiece. The grinding wheel is advanced until it engages the workpiece, at which time, the advance is interrupted. Advancing means are then activated in response to engagement of the grinding wheel and the workpiece to thereafter apply additional force to move the wheel a predetermined further distance, thereby effecting a predetermined depth of cut from the workpiece.

In the preferred embodiment, the grinding wheel is moved at a rapid approach rate by a floating hydraulic cylinder toward the workpiece until contact is made therebetween. A clamping mechanism for the cylinder is actuated in response to the contact to prevent further movement of the floating hydraulic cylinder itself. A metered amount of fluid is then applied to the hydraulic cylinder to move the grinding wheel a further distance against the workpiece to effect a predetermined depth of cut therefrom.

Where the workpiece has multiple diameters with at least one shoulder therebetween, the instant invention can be used as a sidewall-facing attachment. The grinding wheel in this instance is moved longitudinally at a rapid approach rate until it engages the shoulder. Thereafter the predetermined depth of cut removes stock from the shoulder. Apparatus is also provided for advancing the grinding wheel toward the workpiece axis of rotation simultaneously with the grinding of the shoulder to grind both surfaces in one operation. The operation may be automatically controlled by the programming of a card reader or manually initiated by pushbutton to effect the feed movements of the grinding wheel.

The instant invention provides a control system for advancing a grinding wheel without sensing the advance of the wheel during stock removal. Likewise, it is not necessary to sense the removal of the stock in order to terminate the advance of the wheel. Instead, the wheel position is established by advancing it until it engages the workpiece. Then the control system advances the wheel a further predetermined distance to effect a predetermined depth of cut from the workpiece. When the wheel has over that distance, a signal, remote from the workpiece and the wheel, terminates the advance and retracts the wheel.

Accordingly, a primary object of this invention is to provide a grinding machine for effecting a predetermined depth of cut from a workpiece after the grinding wheel engages the workpiece.

A further object is to include a sidewall-facing operation in the automatic cycle of a machine tool to'enable a predetermined depth of cut to be removedrfrom a shoulder formed on a workpiece having multiple diameters.

Another object is to provide'facilities to continue the approach feed rate and the grinding feed rate of. the sidewall facing attachment.

Still another object is to provide means to face the sidewall of a workpiece during the normal plunge grinding operation of an adjacent diameter.

Another object is to control dual feed movements of a cylindrical grinding wheel during the normal grinding operation without increasing the cycle time, and to provide means to control an element of fine feed upon completion of .the sidewall facing operation.

Another object is to provide means to maintain a resisting force or back pressure to counterbalance the increase in thrust load on the wheel spindle during longitudinal movement.

BRIEF DESCRIPTION OF THE DRAWINGS With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawings, wherein:

FIG. 1 is a partial sectional front view of a grinding machine embodying the principles of the invention, showing the grinding wheel, wheel support, spindle and the sidewall facing attachment;

FIG. 2 is a partial end view taken from the right of FIG. 1, showing the mounting of the sidewall-facing attachment;

FIG. 3 is a partial plan view of the wheel support shown in FIG. 1;

FIGS. 4a and 4b are a schematic hydraulic diagram of the feed mechanism for the sidewall-facing attachment; and

FIG. 5 is a wiring diagram showing the control circuit for operating the sidewall feed attachment.

FIG. 6 is a schematic block diagram showing the sidewallfacing attachment driven by a stepping motor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings and particularly to FIG. 1, the is illustrated a sidewall-facing attachment l0 incorporating a longitudinal feed arrangement in accordance with the present invention. The sidewall-facing attachment [0 is used for effecting a predetermined depth of cut from a shoulder 11 or 12 formed on a cylindrical workpiece 13 having adjacent cylindrical diameters l4, l6 and 17.

This invention is described, by way of example, as being applied to a sidewall-facing operation on a cylindrical grinding machine; however, it should be understood that the present invention may be used on the infeed movement of a wheel support on a cylindrical grinding machine or on other types of grinding machines such as surface-grinding machine wherein a preset depth of cut could be removed from an external planar surface of a nonrotatable workpiece.

In the specific embodiment shown, the workpiece I3 is rotatably supported in any conventional manner and is longitudinally positioned relative to the longitudinal position of a grinding wheel 18. The grinding wheel 18 is advanced toward the workpiece by the transverse movement of a wheel support or wheelhead 19. The infeed grinding rate may be varied as shown and described in my copending application, Ser. No. 83l,828, filed June 10, 1969 now U.S. Pat. No. 3,58l,445, granted June 1, 1971 Longitudinal movement of the grinding wheel 18 to the left (FIG. 1) is controlled by the volume of fluid pressure directed to a hydraulic motor or cylinder 20 (FIGS. 2 and 4a). Cylinder 20 which is restrained against movement by spring pressure, houses a piston 21 and piston rod 22 which are advanced to the left rapidly to effect movement of the grinding wheel 18 toward the shoulder 11 for example, at a rapid approach feed rate during a sidewall-facing operation. The rapid approach feed rate continues until the side of the grinding wheel 18 contacts the shoulder 11. Fluid pressure than moved cylinder 20 to the right (FIG. 4a), as pressure from a tension spring 23 is overcome. A sidewall feed-limit switch 17LS is opened which effects the operation of control means to direct fluid pressure to the head end of a hydraulic motor or cylinder 24. A piston 26 and a piston rod 27 housed in the cylinder 24 are advanced to clamp the cylinder 20 against further movement.

Fluid pressure is then directed to the head end of a displacement cylinder 28. The displacement cylinder 28 houses a piston 29 and a piston rod 31, which are advanced to the right (FIG. 4a) to provide a metered amount of displaced fluid to the head end of the cylinder 20. The piston 21 and piston rod 22 are again advanced to the left FIG. 4a) to effect a further longitudinal movement of the grinding wheel 18 to the left (FIG. 1) at a grinding rate feed.

The longitudinal movement of the grinding wheel 18 is accommodated by the conventional construction of a wheel spindle assembly 32, which is housed in the wheelhead 19, as shown in FIG. 1 A spindle 33 is rotatably supported in bearings 34 and 36, which are supported in axially spaced retaining rings 37 and 38 respectively. Each bearing 34 and 36 is positioned in a recess 39 of wheelhead bore 41 and secured by a clamping nut 42, which is threaded to a nut 43 (one shown). The nuts 43 are removably secured to each side of the wheelhead 19.

The spindle 33 is positioned longitudinally within the bore 41 by a plurality of thrust springs 44 (one shown). The thrust springs 44 project from a number of holes spaced circumferentially in a spindle sleeve 47. The spindle sleeve 47 is secured to the spindle 33 to provide an axial force against a shoulder 48 of the spindle 33, through the thrust springs 44 which urge the spindle 33 to the right (FIG. 1), abutting a sleeve 49 against the side of the bearing 36.

The grinding wheel 18 is secured to a wheel center 51 by a ring 50 in a conventional manner. The wheel center 51 is secured to the spindle 33 by a collar 52 which fits in a recess 55 within the wheel center 51 and holds the grinding wheel 18 and the wheel center 51 on the spindle 33 by a screw 53 passing therethrough and threaded in the spindle 33.

The sidewall-facing attachment advances the rotatable spindle 33 longitudinally to the left as shown in FIG. 1, by

clockwise movement of a rotatable lever 54 (FIG. 3). The lever 54 is keyed to a vertical shaft 56 (FIG. 1) by a cap 57 and a screw 58 passing therethrough and threaded in the shaft 56. The shaft 56 is rotatably journaled between a pair of spaced bearings 59, which are housed within a bore 61 within a projection 62 of a cover 63. The bearings 59 are vertically spaced by a sleeve 64. The shaft 56 includes an eccentric portion 66 journaled in a bearing 67, which is housed in a cam 68. The cam 68 is received within an opening 69 formed within the spindle sleeve 49.

A tension spring 71 is connected between a pin 72 and a support member 73 which is secured to the wheelhead 19. The pin 72 is secured to a plate 76 which is removably secured to the cap 57 and includes facilities to increase or decrease the force of the spring 71. The spring 71 maintains a resisting force or back pressure to counterbalance the thrust load on the grinding wheel spindle 33 during the longitudinal movement of the spindle 33. Thus, as the grinding wheel 18 moves toward the workpiece, thereby increasing the thrust load exerted by the springs 44, the pin 72 moves clockwise (FIG. 3)

toward a position where it is in line with the axis of shaft 56 and support member 73, thereby decreasing the back pressure applied by the spring 71. Ideally, the forces applied by the springs 44 and 71 would vary inversely to maintain an approximate constant longitudinal force on the spindle 33.

The piston rod 22 is supported by a yoke member 78, which is pivotably secured to the lever 54 by a stud 79 (FIGS. 2 and 4a). The head end of the cylinder includes a cIevis-mounting 80, which enables a reed member 81 to be pivotably connected to the cylinder 20 by a stud 82. The reed member 81 is secured to a support member 83, through a leaf spring 84 and a clamp member 86, by a screw (not shown). The reed member 81 is slidably supported on an anvil 87, which is secured to a mounting plate 88. The mounting plate 88 is secured to the top of the wheelhead 19 and is positioned to receive the reed member 81.

The support member 83 is secured to the mounting plate 88 and supports the hydraulic motor or cylinder 24 and the sidewall feed-limit switch 17LS. The normally closed limit switch 17LS is positioned to enable the clamp member 86 to open limit switch 17LS by slight movement of cylinder 20 to the right. This occurs when the side of the grinding wheel 18 contacts the shoulder 11 during the approach rate feed of the sidewall-facing operation.

The piston 26 and piston rod 27 are then advanced downwardly by fluid pressure to lock the reed member 81 against the anvil 87, to prevent further movement of the cylinder 20 to the right (FIG. 4a).

The cylinder 20 is urged to the left (FIGS. 2 and 4a) by the tension spring 23. One end of the spring 23 is secured to the head end of the cylinder 20 through a fastener or eyebolt 89 (FIG. 3). The other end of the spring 23 is secured to an adjusting rod 91 which is threaded in a bracket 92. The bracket 92 is secured to the wheelhead 19, and is spaced to provide a strain on the spring 23. The spring 23 provides a force to retain the cylinder 2 against a stop block 93. This arrangement maintains the position of the cylinder 20 during the approach rate feed of the sidewall-facing operation.

The displacement cylinder 28 which regulates the metered flow of fluid to the head end of the cylinder 20, determines the depth of cut from the shoulder 11. The cylinder 28 includes an adjusting knob 94 secured to an adjusting screw 96, which is in threaded engagement with a threaded bore 97 of the head end of cylinder 28. Movement of the adjusting screw 96 alters the stroke of the piston 29 and the piston rod 31 by controlling the volume within the rod end of the cylinder 28.

The cylinder 28 is supported by a member 98 which is secured to the cover 63. A feed rate valve 99 is secured to the head end of the cylinder 28, and includes a throttle valve 100 which controls the flow of fluid being directed to the head end of cylinder 28. Adjustment of the valve 100 controls the rate of longitudinal feed movement of the grinding wheel 18 during the sidewall-facing operation.

A sidewall feed completion limit switch 15LS is carried by a bracket 101, which is secured to the valve 99. A bracket 102 is secured to the end of the piston rod 31 so that an electrical circuit is completed through the limit switch 15LS, when the piston rod 31 is advanced to the right (FIG. 4a) at feed completion. The signal from the limit switch 151.8 is made just before the pin 29 abuts the positive stop provided by a shoulder 95 within the cylinder 28 to stop the sidewall feed.

The rapid approach rate of the longitudinal feed movement is controlled by the adjustment of a throttle valve 104, which controls the flow of fluid to the head end of the cylinder 20. The valve 104 is supported by a bracket 105 which is also secured to the valve 99.

GENERAL MECHANICAL AN HYDRAULIC OPERATION The sidewall-facing sequence is hydraulically operated by the controlled flow of fluid through the hydraulic motor or cylinder 20 to effect the longitudinal movement of the grinding wheel 18 and the spindle 33 toward a shoulder, for example shoulder 11, formed on the cylindrical workpiece 13, as shown in FIG. 1. A predetermined depth of cut removes stock from the shoulder 11, while the smaller adjacent cylindrical diameter 16 is being ground to size.

The grinding wheel 18 and spindle 33 are advanced toward the shoulder 11 at a rapid approach feed rate, which is controlled by the valve 104. The valve 104 regulates the flow of hydraulic fluid from a solenoid valve 106 (FIG. 4b) to the head end of the cylinder 20. The piston 21 is advanced to the left (FIG. 40) until the side of the grinding wheel 18 contacts the shoulder 11. The cylinder 20 is now advanced to the right (FIG. 4a) until limit switch 17LS effects the advancement of the piston 26 and piston rod 27 which locks the cylinder 20 against any further movement The piston 21 within the cylinder 20 is now advanced to the left a small amount, which is determined by the volume of fluid discharged from the rod end of the displacement cylinder 28, to effect a predetermined depth of cut from the shoulder 11. The feed rate for grinding the shoulder 11 is controlled by the throttled flow of fluid through the throttle valve 100 which is coupled to the head end of the cylinder 28.

Reference is now made to FIGS. 4aand 4b with respect to the hydraulic system for controlling the sidewall-facing operation and the controlled movement of the grinding wheel 18 against the workpiece 13. I The hydraulic system includes a pump 107 driven by a motor 108 to direct fluid under pressure from a reservoir or supply tank 109 to a solenoid valve 110 through lines 1 11 and 112. A check valve 113 is included in the line 112 between the pump 107 and the valve 110 to prevent the reverse flow of fluid when the pump is inoperative.

The valve 110 has a line 114 connected to the rod end of the cylinder 24 to reset the piston 26. This permits the cylinder 20 to be reset by the spring 23 against the stop block 93. A line 116 branching from the line 114 is connected to the rod end of the cylinder 20, which enables fluid passing through the valve 110 to reset the piston 21 to the right (FIG. 4a).

A line 117 is connected from the head end of the cylinder 20 to a line 118. The line 118 also connects the rod end of the cylinder 28 to the valve 110 through a connection with line 119. Fluid being discharged from the head end of the cylinder 20 is directed through the lines 1 17 and 118 to reset the piston 29 to the left (FIG. 4a). A line 121 branching from the line 118 includes a restrictor 122 and a check valve 123 to direct any air within the head end of cylinder 20 or within the rod end of cylinder 28 to a drain 124, when piston 21 is reset. A line 126 also connects the valve 99 to the drain 124 for internaLdrainage of the valve 99.

The line 119 coupled to valve 110 is also connected to the solenoid valve 106. The valve 106 is shown in the neutral position and provides means to receive fluid being discharged from the head end of cylinder 28, through lines 128 and 129. A check valve 131 within the valve 99 is connected to the line 128 to allow fluid to bypass the throttle valve 100 in the line 129, and to regulate the desired direction of fluid flow. When the piston 29 is reset to the left (FIG. 4a), fluid is directed through the valve 106 and to a drain 133 by a line 134.

A line 136 branching from the line 112 is connected to a solenoid valve 137. The valve 137, which is shown deenergized, includes a lie 138 which is connected to the head end of the cylinder 24. The line 138 receives fluid being discharged from the head end of the cylinder 24, when the piston 26 is reset. The valve 137 is connected to a return line 139 which enables the discharged fluid to be returned to the supply tank 109.

The line 118, which links lines 117 and 119, enables fluid from the rod end of cylinder 28, and from the head end of the cylinder 20 to be discharged through the valve 110 to a drain 141 by a line 142 when valve 110 is deenergized. A check valve 143 is included in the line 118 between the valve 110 and the branch line 117. The valve 143 prevents the flow of fluid in the reverse direction when the valve 110 is energized.

The valve 106 is connected to a line 144, which is connected to the line 118, and includes the throttle valve 104 and a check valve 146, to provide fluid at the head end of the cylinder 20 during the approach feed rate.

It should be apparent from FIG. 4b that the valves 106, 110, and 137 are spring-loaded with the valve 106 being springloaded at each end, having a neutral position therebetween. The valve 106 has associated therewith at its ends solenoids 26SOL and 31SOL. The valve 110 has associated therewith a solenoid 27SOL, and the valve 137 has associated therewith a solenoid 32SOL. Each solenoid is electrically connected to a control panel 140 in the manner diagrammatically shown.

When the solenoid 27SOL is energized, the valve 110 is shifted to the left (FIG. 4b) which enables hydraulic fluid under pressure to be directed from line 112 to the line 119 through the valve 110. The valve 106 is shifted to the left when the solenoid 26SOL is energized so that fluid pressure is directed from line 119 to line 144 through the valve 106. The line 144 directs fluid through the throttle valve 104 and the check valve 146 to the head end of the cylinder 20 through the line 117.

The piston 21 and the piston rod 22 are urged to the left (FIG. 4a) which pivots the lever 54 and the eccentric portion 66 of the vertical shaft 56 clockwise. The movement of the shaft 56 advances the grinding wheel 18 and the spindle 33 towards the shoulder 11 of the workpiece 13 at an approach fee rate controlled by the flow of fluid through the throttle valve 104. I

Clockwise movement of the lever 54 decreases the force which tension spring 71 applies to the shaft 56, as shown in FIG. 3, until the torque generated on the vertical shaft 56 reaches zero, when the center of the spring 71 is aligned with the center of the shaft 56. This movement maintains a resisting force or back pressure which is reduced proportionally as the load on the thrust springs 44 is increased. Therefore, the work load on piston rod 22 remains constant during the clockwise movement of lever 54.

The continuing flow of fluid to the head end of cylinder 20 overcomes the strain on spring 23 which had restricted movement of the cylinder 20 until the side of the grinding wheel 18 contacted the shoulder 11 of the workpiece 13. The cylinder 20 is then moved to the right.

Movement of the cylinder 20 continues until an electrical signal from the limit switch 17LS deenergizes the solenoid 26SOL, which resets the valve 106. The solenoid 32801. is also energized from the same signal and the valve 137 is positioned to the left (FIG. 4b). Fluid pressure is now directed from the line 136 through the valve 137 through line 138 to the head end of the cylinder 24. The piston 26 and the piston rod 27 are lowered to lock the reed member 81 against the anvil 87 to prevent the cylinder 20 from further movement.

The solenoid 31SOL is energized following a dwell period, and the valve 106 is shifted to the right (FIG. 4b). Fluid under pressure is now directed from the line 119 through the valve 106 to the line 129. The line 129 directs fluid though the valve to the head end of the cylinder 28. The piston 29 and the piston rod 31 are advanced to the right (FIG. 4a), which displaces a predetermined volume of fluid from the rod end of the cylinder 28. The discharged fluid is directed to the head end of the cylinder 20 through the lines 118 and 117. The piston 21 and piston rod 22 are advanced to the left to effect additional clockwise movement of the lever 54 and longitudinal movement of the grinding wheel 18 against the workpiece a distance corresponding to the said predetermined volume of fluid. The movement of grinding wheel 18 continues until the piston 29 engages the shoulder 95, at which time, limit switch ISLS is closed by the bracket 102 by movement of the piston rod 31 to the right.

Although, the sidewall-facing operation is now completed, the valves 106, and 137 are not reset until the wheelhead 19 starts to retract.

OPERATION With reference to FIGS. 4a, 4b,and 5, it is to be understood that the sidewall-facing operation may be automatically controlled by placing a prepunched card (not shown) in a card reader 147, or manually initiated by depressing a pushbutton PB9, when a selector switch SS7 is positioned to ON.

It is to be understood that during the automatic cycle of the machine, the wheelhead 19 will be advanced automatically at a rapid infeed rate following a qualifying signal (not shown) from a suitable size control device as described in my copending application, Ser. No. 83 l ,937, filed June 10, I968.

A qualification relay contact 48CR1 is closed to complete a circuit through a normally closed on-size contact 50CR1 which energizes an .infeed relay 27CR to effect the advance of the wheelhead 19. Contacts 27CR1, 27CR2 and 27CR3 are closed by the energization of the relay 27CR, to enable the sidewall-facing operation to be effected.

The wheelhead 19 is advanced first at a rapid infeed rate and then at a slow plunge feed rate. The manner in which the wheel support 19 is advanced is not a part of this invention and is not specifically disclosed herein, and may be accomplished in any desired manner.

A slow grinding feed rate is actuated following the rapid infeed movement, as a contact 27CR4 is closed by the energization of the relay 27CR. The closing of the contact 27CR4 energizes a grinding feed solenoid 13SOL and a solenoid valve 149 (FIG. 4b) is positioned to the right. Fluid pressure from the line 112 is directed through the valve 149 to a line 150, which is connected to the head end of a cylinder 15]. A piston 152 within the cylinder 151 is shifted to the left to advance the wheelhead 19 through a feed mechanism 153. Fluid pressure from the rod end of the cylinder 151 is directed through the valve 149 by a line 154, and into the tank 109.

It is to be understood that a contact K3 is closed by the functioning of the card reader 147 at the beginning of the automatic cycle, when a shoulder-grinding operation is programmed. Closing of the contact K3 completes a circuit to energize an automatic relay 42CR. A contact 42CR1 is closed which completes a circuit to energize a feed stop relay 31CR.

A contact 31CR1 is then closed which completes a circuit to energize a feed stop solenoid 16SOL, which shifts a valve (not shown) to allow a normal slow plunge feed of the wheel head 19 and the associated grinding wheel 18.

The sidewall-facing operation normally should not be started until after the rapid infeed movement of the wheelhead 19 has been completed, which closes a feed start limit switch 16LS from a cam (unnumbered) on the handwheel 148 as shown in FIG. 4b.

A contact K7 is closed by the card reader 147 prior to the grinding cycle, whenever sidewall facing or shoulder grinding is programmed in conjunction with the grinding of each adjacent cylindrical diameter 16 or 17. Closing of the contact K7 completes a circuit through contacts 27CR1 and 42CR2, limit switch 16LS, selector switch SS7, and normally closed contact 47CR1, to energize a sidewall feed relay 65CR.

A contact 65CR1 then closes to energize the solenoid 27SOL to thereby position the valve 110 to direct fluid pressure from the pump 107 to effect the start of the sidewall operation.

A normally closed contact 65CR2 is opened when the relay 65CR is energized, to prevent a feed completion relay 51CR from being energized until the sidewall-facing operation is completed.

A contact 65CR3 is closed when the relay 65CR is energized to provide a holding circuit around the limit switch l6LS. A contact 65CR4 is also closed.

A sidewall approach relay 66CR is energized simultaneously with the energization of the relay 65CR through the limit switch 17LS, which is normally closed.

When the relay 66CR is energized, a normally closed contact 66CR] is opened to prevent a sidewall clamp relay 74CR and a sidewall feed start relay 75CR from being energized.

Energization of the relay 66CR also closes a contact 66CR2 which energizes the solenoid 26SOL. This positions the valve 106 to the left (FIG. 4b), which directs fluid pressure from the valve 106 to the head end of the cylinder 20, through the throttle valve 104 and the check valve 146.

The piston 21 is advanced to the left (FIG. 4a) at a rapid rate controlled by the regulated flow of fluid through the throttle valve 104, to effect clockwise movement of the lever 54.

Clockwise movement of the lever 54 advances .the wheel spindle 33 longitudinally to the left (FIG 1) at an approach feed rate until the side of the grinding wheel 18 contacts the shoulder of the workpiece 13. The force of spring 23, which retains cylinder 20 against the stop block 93, is overcome by an increase of fluid pressure in cylinder 20 when the grinding wheel 18 is stopped by the shoulder 11. The cylinder 20 is then moved slightly to the right (FIG. 4a) by said fluid pressure until the limit switch '1 7 LS is opened.

Opening of the limit switch 17LS deenergizes the relay 66CR. Therefore, the normally closed contact 66CR1 is closed to complete a circuit to energize the sidewall clamp relay 74CR through the contact 65CR4.

Deenergization of the relay 66CR opens the contact 66CR2 which interrupts the circuit to deenergize the solenoid 26SOL. The valve 106 is returned to its neutral position by spring pressure and the approach feed rate is stopped.

Energization of the relay 74CR closes a contact 74CR1 which energizes the solenoid 32SOL to thereby'position the valve 137 to the left (FIG. 4b), directing fluid pressure to the head end of the cylinder 24. The piston 26 and piston rod 27 are lowered to lock the reed member 81. against the anvil 87, to prevent the cylinder 20 from further movement.

Energization of the relay 74CR also closes a contact 74CR2 which completes a circuit to energize feed delay relay 9TR through the contact 27CR3, which was closed at the start of rapid infeed. The contact 9TR1 is closed following a timed interval to allow the cylinder 20 to be clamped and to complete a circuit to energize the sidewall feed start relay 75CR.

Energization of the relay 75CR closes a contact 75CR1 to complete a circuit to energize the solenoid 31SOL. The solenoid 31SOL then positions the valve 106 to the right (FIG. 4b), directing fluid pressure through line 129 to the head end of the displacement cylinder 28 at a rate controlled by the throttle valve 100. The piston 29 is advanced to the right (FIG. 4a), which directs fluid pressure to the head end of the cylinder 20 through line 117.

The piston 21 is advanced to the left which effects additional clockwise movement of the lever 54 and further movement of the spindle 33 toward the shoulder at a grinding feed rate.

A predetennined depth of cut removes stock from the shoulder l 1 which continues until the bracket 102 of the piston rod 31 closes the limit switch 15LS and the piston 29 engages the shoulder 95. A feed completion limit switch 14LS is closed by the cam (unnumbered) on the handwheel 148 (FIG. 4b), which completes a circuit through the limit switch 15LS, to energize the feed completion relay 5lCR.

The energization of the relay 5lCR advances the wheelhead 19 at a fine plunge feed rate following a dwell or time period, to allow the wheel to spark out. The wheelhead l9 and grinding wheel 18 will continue to be advanced through a fine feed system until size is obtained on a gauging device (not shown). An on-size relay (not shown) is energized which opens the normally closed contact 50CR1 to energize the relay 27CR.

Deenergization of the relay 27CR retracts the wheelhead 19 in a conventional manner and opens the contacts 27CR1, 27CR2 and 27CR3. Opening of the contact 27CR] interrupts a circuit to deenergize the relay 65CR, which opens contacts 65CRl, 65CR3 and 65CR4. The solenoid 27SOL is deenergized by the opening of the contact 65CRl, and the valve is reset t the right by spring pressure.

Opening of the contacts 27CR1 and 65CR4 interrupts the circuit to deenergize the relay 74CR, which opens the contact 74CR1. Opening of the contact 74CR] deenergizes the solenoid 32SOL, which permits the valve 137 to be reset to the right by spring pressure.

The opening of contact 27CR3 deenergizes the relay 9TR, which opens the contact 9TR1. Opening of the contact 9TR1 deenergizes the relay 75CR and opens the contact 7SCRl. The solenoid 31SOL is then deenergized by the opening of the contact 75CR1 and the valve 106 is reset to the left to its neutral position.

The valves 106, 110, and 137 are positioned to direct hydraulic fluid to reset the pistons 21, 26 and 29 in preparation for the next sidewall-facing operation.

Special attention should be given to the above operation which was performed without the use of an electrical load control relay to stop the approach feed rate when the grinding wheel 18 contacted the workpiece 13. it should also be noted that the advance of the grinding wheel 18 after contact with sidewall, was accomplished by means of metered fluid from the displacement cylinder 28, without the use of any electrical sensing of measuring device to stop the sidewall-facing operatron.

As an alternate method of operation, the automatic sidewall-facing operation may also be effected by depressing the pushbutton PB9 during SETUP. This should occur when the card reader 147 is on DIAL, and when selector switch SS7 is positioned to ON, as the contact 27CR3 is closed at the start of the rapid infeed.

The closing of pushbutton PB9 completes a circuit through the selector switch SS7 and the normally closed contact 47CR1 to energize the sidewall feed relay 65CR. The sidewall approach relay 66CR is also energized as limit switch 17LS is normally closed.

Energization of the relay 65CR closes the contact 65CR3 to provide a holding circuit around the pushbutton PB9, which may now be released. The complete sidewall operation may now be effected as previously described.

The automatic sidewall-facing selector switch SS7 may be turned to the OFF position which interrupts the automatic cycle. This provides the machine operator with means to override the programmed card reader 147 and deenergize the feed stop relay 31CR to prevent infeed grinding.

The selector switch SS7 is positioned to of when the shoulder to be ground is under the normal height required to provide sufficient resistance to stop the sidewall approach feed rate. Shoulders of this type are then ground manually by movement of a carriage (not shown) by a traverse handwheel (not shown) in a conventional manner. It is also possible to arrange the infeed movement of the grinding wheel 18 simultaneously with the longitudinal movement effected by the sidewall-facing operation as shown in FIG. 6. The diameter 16 will be ground to size while a predetermined amount of stock is being removed from the shoulder 11.

While the invention is described in detail with reference to a hydraulic apparatus for effecting a predetermined depth of cut after the grinding wheel engages the workpiece, it is to be understood that an electrical drive means could be used as shown in FIG. 6. For example, a load control relay 155 could be used to sense the contact of the grinding wheel 18 with the workpiece W after which the same electrical motor, which had advanced the grinding wheel to the workpiece W, may be used to advance the grinding wheel the predetermined distance. A stepping motor 156 could be used, for example, with appropriate control circuit means 157 for rotating the motor 156 a known amount to advance the grinding wheel a predetermined amount by means of a coupling or gear reduction mechanism 158 connected to the shaft 56. It is to be understood that only a preferred embodiment of the invention has been specifically illustrated and described, and variations may be made thereto without departing from the invention, as defined in the appended claims.

lclaim:

1. In a grinding machine for efl'ecting a predetermined depth of cut from a workpiece, the machine including a grinding wheel, means for supporting and rotating said wheel, and means for supporting the workpiece, wherein the improvement comprises:

a. means for moving said grinding wheel until it engages said workpiece, and

b. means operable in response to engagement of said grinding wheel and said workpiece for thereafter applying additional force for moving said wheel a predetermined distance beyond the point of engagement.

2. The grinding machine claim 1, in which the means operable in response to engagement of the grinding wheel and workpiece includes control means for resuming the movement of the grinding wheel for performing a grinding operation.

3. The grinding machine of claim I in which the means operable in response to engagement of the grinding wheel and workpiece includes a measuring means for determining the extent of advance of said grinding wheel.

4. In a cylindrical grinding machine for grinding a multiplediameter workpiece having a shoulder between said diameters and including a grinding wheel, and means for supporting and rotating the grinding wheel and the workpiece, wherein the improvement comprises:

a. first hydraulic means for moving said grinding wheel longitudinally until it engages said shoulder and then interrupting the longitudinal advance of the wheel;

b. second hydraulic means for then further longitudinally moving said wheel a predetermined distance thereby effecting a predetermined depth of cut from the said shoulder, and

c. electrical means for sequentially operating both said hydraulic moving means.

5. A machine as recited in claim 4 which further includes, means for advancing said wheel inwardly toward the workpiece axis of rotation to grind the diameter of the rotating workpiece simultaneously with the grinding of the shoulder.

6. A machine as recited in claim 4 wherein said first hydraulic means includes:

a. a first hydraulic motor having a cylinder and a pistondriven rod;

b. a lever having a cam on one end and connected at the other end to the piston rod of the hydraulic cylinder, said cam being effective to advance the grinding wheel longitudinally upon application of pressure to the piston within the cylinder;

. spring means for preloading the cylinder against at stop, said cylinder remaining against the stop until the wheel engages the shoulder, whereupon the cylinder is urged away from the stop; and

d. means responsive to movement of said cylinder for clamping the cylinder against further movement.

7. A machine as recited in claim 6, wherein said second hydraulic means for moving the wheel a predetermined longitudinal distance includes:

a. a hydraulic displacement cylinder;

b. conduit means for connecting said displacement cylinder to said first hydraulic motor to convey metered amounts of fluid thereto; and

c. means responsive to the wheel engaging the shoulder for directing fluid pressure to the displacement cylinder to discharge a metered amount of fluid to said first hydraulic motor, thereby moving the grinding wheel said predetermined longitudinal distance.

8. A machine as recited in claim 6, wherein said means for supporting the wheel includes a wheel spindle having thrust springs therein which urge the grinding wheel away from the shoulder, said springs being compressed as the wheel moves toward the shoulder, thereby exerting an increasingly greaterrestraining force against movement; and which further comprises:

a. a counterbalancing spring connected to said lever, said spring acting to urge the lever in the same direction as the thrust springs of the spindle, but said counterbalancing spring forces varying inversely to the thrust springs during longitudinal movement of the grinding wheel toward the workpiece to maintain approximately a constant total spring force on said spindle.

9. In a grinding machine, means for making a cut of predetermined depth on a workpiece, the machine including a grinding wheel, means for supporting and rotating said wheel, and means for supporting the workpiece, wherein the improvement comprises:

a. a first hydraulic motor having a cylinder and pistondriven rod and means connecting the piston-driven rod to the wheel-supporting means for moving said grinding wheel at a rapid approach rate toward the workpiece until contact is made therebetween;

b. means for normally urging the cylinder of said motor against a stop, said means being overcome when the grinding wheel contacts the workpiece to move the cylinder away from the stop;

c. means responsive to said cylinder movement for clamping said cylinder against further movement; and

d. means for then supplying a'metered amount of fluid to said cylinder to move the piston-driven rod and thereby the grinding wheel a predetermined further distance against the workpiece.

10. -A' machine as recited in claim 9, wherein said means for supplying a metered amount of fluid includes:

a. hydraulic means for discharging metered amounts of fluid therefrom; and

b. means actuated by the movement of said first hydraulic cylinder for effecting said metering of fluid from said displacement cylinder.

ll. In a grinding machine for effecting a predetermined depth of cut from a workpiece, the machine including a grinding wheel, means for supporting and rotating said wheel, and means for supporting the workpiece, wherein the improvement comprises:

a. hydraulic means including a hydraulic motor having a' cylinder and a piston-driven rod for positioning the grinding wheel;

b. a mechanical linkage connecting said hydraulic motor to the wheel-supporting means for moving said grinding wheel at a rapid approach rate toward the workpiece until contact is made therebetween;

c. biasing means for normally urging said cylinder against a stop, said biasing means being overcome when the grinding wheel contacts the workpiece to move the cylinder away from the stop;

d. means responsive to said cylinder movement for clamping said cylinder against further movement; and

e. means for then supplying a metered amount of fluid to said cylinder to displace said piston-driven rod and move the grinding wheel a further distance against the workpiece to effect a predetermined depth of cut therefrom.

12. A machine as recited in claim 11, wherein said mechanical linkage includes:

a. a wheel spindle on which is mounted the grinding wheel,

and

b. a lever having a cam at one end in engagement with the spindle, and connected at the other end to the pistondriven rod of a driving motor, so that movement of said rod in one direction advances the wheel spindle longitudinally toward the workpiece.

52 g TJNTTED STATES PATENT QFFICE CERTIFICATE CF CCREC'HCN Patent No. 3 $365661 Dated January 25, 1972 1 Inventofls) a ph E. Price It is certified that error'appeara 1n the above-identified patent and that said Letters Patent are hereby corrected as ahown'below:

Column 1, line 21, "transverse" should' be; ---t1mave rseline 69, "over." should be. --'-moved-'-.

Column 2, line 5, "continue" should be '--'con'trol line #6, "the" should be +t-her 'e I line 57,; before "surface" inse'rt -j a--'.

Column 3 line 3 "than moved" shoiuld be '--t hen moves-5 line #7, "journaled" should be" -journal-led-fi line 51.," "journaled". should be j uTnalled-Q,

Column A, line "2'? should be V line 50, "pin'" should be -lpiston 1 line 57, "AN" "should be, -;-AND--..t

Column 5 line 13 ;"L aand" should-be --ha. andline 51, "lie" should be --line--'.

Column 6, line '17, "fee" should be --feed--.

line 38, after "137" insert --and--.

Column 8, line 21, after "Energize" insert ---a Sid Wall-- I line 51, "energize" should be -deenergize-..

line 58, "t" should be -'--to-'-.

Column 9, line 8, "of" should be; --o r--. 4 I

I line 30, ""off should be --"OFF"'--.

line 5b,, after the period, the following sentence is separate paragraph.

Claim 2, line 1, after "machine" insert -of Claim 6, line 10, at" should be --a--.

Signed and 'sealed this. 22nd day of August 1972.

(SEAL) Attest:

EDWARD MTLTTcHER'JJR. R BERT GOTTSCHALK mmissioner of latents Attesting Officer 

1. In a grinding machine for effecting a predetermined depth of cut from a workpiece, the machine including a grinding wheel, means for supporting and rotating said wheel, and means for supporting the workpiece, wherein the improvement comprises: a. means for moving said grinding wheel until it engages said workpiece, and b. means operable in response to engagement of said grinding wheel and said workpiece for thereafter applying additional force for moving said wheel a predetermined distance beyond the point of engagement.
 2. The grinding machine of claim 1, in which the means operable in response to engagement of the grinding wheel and workpiece includes control means for resuming the movement of the grinding wheel for performing a grinding operation.
 3. The grinding machine of claim 1 in which the means operable in response to engagement of the grinding wheel and workpiece includes a measuring means for determining the extent of advance of said grinding wheel.
 4. In a cylindrical grinding machine for grinding a multiple-diameter workpiece having a shoulder between said diameters and including a grinding wheel, and means for supporting and rotating the grinding wheel and the workpiece, wherein the improvement comprises: a. first hydraulic means for moving said grinding wheel longitudinally until it engages said shoulder and then interrupting the longitudinal advance of the wheel; b. second hydraulic means for then further longitudinally moving said wheel a predetermined distance thereby effecting a predetermined depth of cut from the said shoulder, and c. electrical means for sequentially operating both said hydraulic moving meaNs.
 5. A machine as recited in claim 4 which further includes, means for advancing said wheel inwardly toward the workpiece axis of rotation to grind the diameter of the rotating workpiece simultaneously with the grinding of the shoulder.
 6. A machine as recited in claim 4 wherein said first hydraulic means includes: a. a first hydraulic motor having a cylinder and a piston-driven rod; b. a lever having a cam on one end and connected at the other end to the piston rod of the hydraulic cylinder, said cam being effective to advance the grinding wheel longitudinally upon application of pressure to the piston within the cylinder; c. spring means for preloading the cylinder against a stop, said cylinder remaining against the stop until the wheel engages the shoulder, whereupon the cylinder is urged away from the stop; and d. means responsive to movement of said cylinder for clamping the cylinder against further movement.
 7. A machine as recited in claim 6, wherein said second hydraulic means for moving the wheel a predetermined longitudinal distance includes: a. a hydraulic displacement cylinder; b. conduit means for connecting said displacement cylinder to said first hydraulic motor to convey metered amounts of fluid thereto; and c. means responsive to the wheel engaging the shoulder for directing fluid pressure to the displacement cylinder to discharge a metered amount of fluid to said first hydraulic motor, thereby moving the grinding wheel said predetermined longitudinal distance.
 8. A machine as recited in claim 6, wherein said means for supporting the wheel includes a wheel spindle having thrust springs therein which urge the grinding wheel away from the shoulder, said springs being compressed as the wheel moves toward the shoulder, thereby exerting an increasingly greater restraining force against movement; and which further comprises: a. a counterbalancing spring connected to said lever, said spring acting to urge the lever in the same direction as the thrust springs of the spindle, but said counterbalancing spring forces varying inversely to the thrust springs during longitudinal movement of the grinding wheel toward the workpiece to maintain approximately a constant total spring force on said spindle.
 9. In a grinding machine, means for making a cut of predetermined depth on a workpiece, the machine including a grinding wheel, means for supporting and rotating said wheel, and means for supporting the workpiece, wherein the improvement comprises: a. a first hydraulic motor having a cylinder and piston-driven rod and means connecting the piston-driven rod to the wheel-supporting means for moving said grinding wheel at a rapid approach rate toward the workpiece until contact is made therebetween; b. means for normally urging the cylinder of said motor against a stop, said means being overcome when the grinding wheel contacts the workpiece to move the cylinder away from the stop; c. means responsive to said cylinder movement for clamping said cylinder against further movement; and d. means for then supplying a metered amount of fluid to said cylinder to move the piston-driven rod and thereby the grinding wheel a predetermined further distance against the workpiece.
 10. A machine as recited in claim 9, wherein said means for supplying a metered amount of fluid includes: a. hydraulic means for discharging metered amounts of fluid therefrom; and b. means actuated by the movement of said first hydraulic cylinder for effecting said metering of fluid from said displacement cylinder.
 11. In a grinding machine for effecting a predetermined depth of cut from a workpiece, the machine including a grinding wheel, means for supporting and rotating said wheel, and means for supporting the workpiece, wherein the improvement comprises: a. hydraulic means including a hydraulic motor having a cylinder and a piston-driven rod for positioning the grinding wheel; b. a mechanical linkage connectiNg said hydraulic motor to the wheel-supporting means for moving said grinding wheel at a rapid approach rate toward the workpiece until contact is made therebetween; c. biasing means for normally urging said cylinder against a stop, said biasing means being overcome when the grinding wheel contacts the workpiece to move the cylinder away from the stop; d. means responsive to said cylinder movement for clamping said cylinder against further movement; and e. means for then supplying a metered amount of fluid to said cylinder to displace said piston-driven rod and move the grinding wheel a further distance against the workpiece to effect a predetermined depth of cut therefrom.
 12. A machine as recited in claim 11, wherein said mechanical linkage includes: a. a wheel spindle on which is mounted the grinding wheel, and b. a lever having a cam at one end in engagement with the spindle, and connected at the other end to the piston-driven rod of a driving motor, so that movement of said rod in one direction advances the wheel spindle longitudinally toward the workpiece. 